The unit for atomic mass is

A. Gram

B. Amu

C. Pound

D. None of the above

It's measured in Amu, so the answer is B.

The unit of atomic mass is Amu.

(B) is correct option.

Explanation:

Atomic mass:

The mass of a single atom of a chemical element.

An atom made by the proton, electron and neutron.

One atomic mass unit is explained by one by twelve of the mass of a single carbon - twelve atom.

We know that,

Gram is the unit of mass in C. G. S unit.

Amu is the unit of atomic mass.

Pound is the unit of mass in F. P. S units.

Hence, The unit of atomic mass is Amu.